1. Field
Embodiments of the present invention relate to a rechargeable battery.
2. Description of the Related Art
Demand for a rechargeable battery as an energy source has increased as demand for technical development of a mobile device has increased. A rechargeable battery differs from a primary battery in that the former is configured to be repeatedly charged and discharged, while the latter is configured to irreversibly convert chemical energy to electrical energy.
A small rechargeable battery is often used as a power supply for small electronic devices, such as cellular phones, notebook computers, and camcorders, while a medium or large rechargeable battery is often used as a power supply for driving motors in hybrid vehicles and electric vehicles.
For example, a pouch-type rechargeable battery includes an electrode assembly that performs charging and discharging, a pouch that accommodates the electrode assembly and an electrolyte solution, and a lead tab that draws the electrode assembly to the outside of the pouch.
Electronic devices require variously sized and shaped rechargeable batteries, depending on the type, size, and shape of an inner space of the electronic device. However, a rechargeable battery having a cylindrical shape or a rectangular parallelepiped shape cannot be effectively accommodated in an accommodating space of some electronic devices.
As such, a pouch-type rechargeable battery may have an irregular shape having a curved portion, rather than having a regular shape, such as a rectangular parallelepiped, or may have a curved and flexible structure while having a rectangular parallelepiped shape to be effectively accommodated in the inner space of the electronic device.
In a rechargeable battery, a sealing portion is provided at an outer edge of a pouch accommodating the electrode assembly, and the sealing portion is folded and then attached to a side surface of the pouch. However, when the pouch has an irregular shape having a curved portion formed at an outer edge thereof, a sealing portion provided in the outer edge of the pouch may form wrinkles in an external circumference (or periphery) due to a difference in diameter between the sealing portion and the pouch.
Further, wrinkles of the sealing portion may be different from each other depending on the shape (or irregularity) of the rechargeable battery. As such, spaces formed between the side surface of the pouch, where the electrode assembly is installed, and the sealing portion may have different sizes.
The wrinkles of the sealing portion, and the spaces formed between the side surface of the pouch and the sealing portion, may cause an increase of the entire volume, and may decrease energy density of the rechargeable battery.
The above information disclosed in this Background section is only for enhancement of understanding of the background of embodiments of the invention, and therefore it may contain information that does not form the prior art.